In order to obtain maximum area coverage for programming, the RF broadcast industry usually places its transmitting antennas on tall towers, often in excess of 1,000 feet in height.
The RF power is directed from the transmitter at ground level to the antenna on the tower by connecting the two units to each other through a transmission line.
In order to attach a transmission line to the supporting tower, extreme care must be exercised to avoid over-stressing the transmission line due to differential thermal expansion between the transmission line and the support tower. Differential movement of ten (10) inches can be anticipated in a typical one thousand (1,000) foot system.
For example, one of the more common transmission lines, waveguide, currently requires a spring hanger for each vertical section (approximately twelve [12] feet) to provide vertical weight support and lateral movement restraint while allowing for differential expansion. These hangers are bulky, heavy, expensive, and require extensive mounting provisioning on the support tower. These units are also awkward to tension correctly on the transmission line, and due to their pivot arm geometry, they introduce undesirable motion as the transmission line expands or contracts vertically.
The object of the invention is to provide a less complex, less expensive method to support transmission line on towers, and to eliminate the undesired lateral motion.
Rather than individually supporting each transmission line section, the invention permits support of multiple transmission line sections each with a single spring hanger assembly. The design permits tower mounting at any convenient level. Structural integrity is enhanced by attachment to the transmission line at the flange joint rather than clamping to the thin, fragile transmission line wall as required by previous existing designs.
Furthermore, the lateral restraint system is separated from the vertical support system, which allows simple bands with wear buttons to be placed at convenient locations on the tower face, as required.